scholarly journals Electrochemical Impedance Immunosensor Based on Self-Assembled Monolayers for Rapid Detection of Escherichia coli O157:H7 with Signal Amplification Using Lectin

Sensors ◽  
2015 ◽  
Vol 15 (8) ◽  
pp. 19212-19224 ◽  
Author(s):  
Zhanming Li ◽  
Yingchun Fu ◽  
Weihuan Fang ◽  
Yanbin Li
Keyword(s):  
Escherichia Coli ◽  
Signal Amplification ◽  
Rapid Detection ◽  
Electrochemical Impedance ◽  
Self Assembled Monolayers ◽  
Escherichia Coli O157 ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Impedance Immunosensor

scholarly journals Microfluidic Impedance Biosensor Chips Using Sensing Layers Based on DNA-Based Self-Assembled Monolayers for Label-Free Detection of Proteins

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 80
Author(s):  
Khaled Alsabbagh ◽  
Tim Hornung ◽  
Achim Voigt ◽  
Sahba Sadir ◽  
Taleieh Rajabi ◽  
...  
Keyword(s):  
Troponin I ◽  
Electrochemical Impedance ◽  
Specific Binding ◽  
Self Assembled Monolayers ◽  
Significant Shift ◽  
Label Free ◽  
Label Free Detection ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Biosensor Chip

A microfluidic chip for electrochemical impedance spectroscopy (EIS) is presented as bio-sensor for label-free detection of proteins by using the example of cardiac troponin I. Troponin I is one of the most specific diagnostic serum biomarkers for myocardial infarction. The microfluidic impedance biosensor chip presented here consists of a microscope glass slide serving as base plate, sputtered electrodes, and a polydimethylsiloxane (PDMS) microchannel. Electrode functionalization protocols were developed considering a possible charge transfer through the sensing layer, in addition to analyte-specific binding by corresponding antibodies and reduction of nonspecific protein adsorption to prevent false-positive signals. Reagents tested for self-assembled monolayers (SAMs) on gold electrodes included thiolated hydrocarbons and thiolated oligonucleotides, where SAMs based on the latter showed a better performance. The corresponding antibody was covalently coupled on the SAM using carbodiimide chemistry. Sampling and measurement took only a few minutes. Application of a human serum albumin (HSA) sample, 1000 ng/mL, led to negligible impedance changes, while application of a troponin I sample, 1 ng/mL, led to a significant shift in the Nyquist plot. The results are promising regarding specific detection of clinically relevant concentrations of biomarkers, such as cardiac markers, with the newly developed microfluidic impedance biosensor chip.

scholarly journals Corrosion Protection of AA7075 Aluminium Alloy by Trimethoxy-Silanes Self-Assembled Monolayers

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Rodrigo S. Neves ◽  
Daiane P. B. Silva ◽  
Artur J. Motheo
Keyword(s):  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Reduction Reaction ◽  
Self Assembled Monolayers ◽  
Organic Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Surface Modified ◽  
Trimethoxy Silane

This study presents electrochemical data concerning the aluminium alloy AA7075 surface modified by self-assembled monolayers (SAMs) of octadecyl-trimethoxy-silane and propyl-trimethoxy-silane. Polarisation curves have shown SAMs blocking effect, as they partially block the oxygen reduction reaction and displace the corrosion potential to positive values. Electrochemical impedance spectroscopy experiments have suggested that the protective effect comes from the oxide layer stabilization by the organic monolayers, which block the corroding species diffusion to the surface. These results show the potential of using methoxy-silanes SAMs as corrosion protective coatings; however, they are also indicative of the superior octadecyl-trimethoxy-silane protective characteristics.

scholarly journals An impedance investigation of corrosion protection of copper by self-assembled monolayers of alkanethiols in aqueous solution

2004 ◽  
Vol 69 (10) ◽  
pp. 791-805 ◽  
Author(s):  
Guiyan Li ◽  
Houyi Ma ◽  
Yongli Jiao ◽  
Shrnhao Chen
Keyword(s):  
Equivalent Circuit ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Copper Substrate ◽  
Self Assembled Monolayers ◽  
Copper Surfaces ◽  
Hydrophobic Barrier ◽  
Assembled Monolayers ◽  
Covered Electrodes ◽  
Self Assembled

Self-assembled monolayers (SAMs) of three n-alkanethiols, 1-octadecanethiol (C18SH), 1-dodecanethiol (C12SH), and 1-hexanethiol (C6SH), were formed on fresh, oxide- free copper surfaces obtained by HNO3 etching. The corrosion protection abilities of the three alkanethiol SAM s were evaluated in 0.2 mol cm-3 NaCl, 0.2 mol cm-3 HCl and 0.2 mol dm?3 H2SO4 solutions using the electrochemical impedance spectroscopy (EIS) method. The SAMs act as a hydrophobic barrier layer, which effectively prevents the copper substrate from contacting corrosive ions, thereby inhibiting corrosion of the copper to a considerable degree. A general equivalent circuit for the SAM-covered electrodes was proposed, bymeans of which the impedance behavior of the electrodes was interpreted and the corresponding electrochemical parameters were acquired. In addition, the quality of the SAMs and development of defects in the SAMs were also been evaluated based on the equivalent circuit. The dependence of the capacitance of the SAMs on the applied potentials was used to determine the stability of the SAMs at the applied potentials.

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